The present invention relates to a layer system for the rotor/stator seal of a turbomachine, in particular a compressor, a method for producing this type of layer system, and a turbomachine, in particular a compressor having this type of layer system.
Although it is applicable to any turbomachine, the present invention as well as its underlying problem will be explained in more detail with reference to a compressor.
In running in shroud-free compressor guide vanes of a stator into a rotor of a turbomachine, the requirements that are to be fulfilled include protecting the rotor from damage and simultaneously enabling a running in of the compressor guide vanes into the rotor that is as deep as possible in order to assure an optimized running gap between the tips of the compressor guide vanes and the rotor. This must not lead to damage of the compressor guide vanes, however.
DE 102 25 532 C1 describes a layer system for a rotor/stator seal of a turbomachine, in particular a gas turbine, which is introduced onto a metal component and can be run in opposite another component that can move relative to it, and, which is characterized by an adhesive layer introduced on the metal component as well as a running-in coating comprising at least two layers introduced thereon for improving the service life and the running-in capability, whereby the first layer delimiting the adhesive layer is harder relative to the second layer and whereby the second layer can be run in.
DE 20 2005 020 695 U1 describes a layer system for protecting components of gas turbines from oxidation and corrosion. The layer system has a metal bonding layer for binding to a substrate and an inner ceramic layer introduced on the metal bonding layer as well as outer ceramic layer introduced on the inner ceramic layer.
DE 10 2004 050 474 A1 describes a method for producing a component that is coated with an anti-wear coating, in particular an anti-corrosion coating or an anti-erosion coating, in particular a gas-turbine component, with the steps: providing a component to be coated on one component surface; at least partially coating the component on its component surface with an anti-wear coating of at least two layers, whereby the anti-wear coating comprises at least one relatively soft layer and at least one relatively hard layer; and surface hardening the at least partially coated component on its coated surface.
It is a disadvantage in these systems that the covering layer is extremely hard and only an extremely limited running in would be possible without massive damage to the vane or the coating. In fact, if a rotor protection were to be assured, the guide vanes would be abrasively worn, however. Understandably, this should be prevented.